body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background: linear-gradient(to bottom, #87CEEB 0%, #87CEEB 50%, #32CD32 50%, #32CD32 100%);
}

#gameCanvas {
    border: 1px solid #000;
    background-color: rgba(255, 255, 255, 0.8); /* 使画布背景半透明 */
}
